Embodiments of the present invention relate to a method and a device for dispensing sealant and a liquid crystal display (LCD) panel.
Recently, liquid crystal displays (LCDs) have being replacing cathode ray tube (CRT) displays and prevailing in the market of displays for televisions, computers and the like due to the characteristics of small volume, occupying relatively small space, etc. A LCD panel is formed by attaching an array substrate to a color filter substrate with a space therebetween and liquid crystal materials are disposed within the space. Generally, when the array substrate is attached to the color filter substrate, sealant is used to maintain the airproof state of the space between the array substrate and the color filter substrate and enclose liquid crystal materials within the space between the array substrate and the color filter substrate without exposing to exterior environment, and thus the cell gap between the substrates can be maintained and the reliability of the liquid crystal display can be sustained.
The sealant mainly comprises resin and can be of thermal curing type or light curing type. The thermal curing sealant has higher adhesion strength but longer curing time; in contrast, the light curing sealant has lower adhesion strength but shorter curing time. Generally, these two types of sealants are used in mixture based on their different characteristics, that is, in a form of a mixture sealant, which can be obtained by uniformly mixing the thermal curing sealant and the light curing sealant by stirring.
FIG. 1 is a schematic view showing a structure of a conventional LCD panel, and FIG. 2 is a sectional view thereof. The conventional LCD panel 100 comprises common transfer members 1, a sealant member 2, a liquid crystal layer 3, an array substrate 5, a color filter substrate 4, and spacers 6. The sealant member 2 is arranged along the four edges of the LCD panel 100 to prevent leakage of the liquid crystal materials of the liquid crystal layer 3 and assist in maintaining the cell gap of the panel. FIG. 3 is a schematic view showing a dispenser head of a conventional dispensing device for dispensing sealant. As shown in FIG. 3, only one channel 19 is provided in the dispenser head of the conventional dispensing device. FIG. 4 is a sectional view showing a configuration of a conventional sealant member, and as shown in FIG. 4, only a sealant member with uniform composition can be obtained by using the dispenser head.
The cell process for large-sized LCD panels comprises the steps of dropping liquid crystal materials, dispensing sealant, vacuum aligning, ultraviolet curing or thermal curing, and the like. Before the vacuum aligning process, the liquid crystal materials and the sealant are applied onto the array substrate and the color filter substrate, respectively; after the ultraviolet curing process, the distance between the liquid crystal materials and the sealant becomes quite small; during or after the above thermal curing process, the liquid crystal materials and the sealant may contact with each other. In the conventional LCD panel, the sealant has a homogenous configuration. In this case, longer curing time is necessary when thermal curing sealant is used, and lower adhesion strength is exhibited when light curing sealant is used although the curing time is reduced. The liquid crystal materials and the sealant may contaminate each other even when a mixture sealant is used. In addition, when sealant that is not completely cured contacts with the liquid crystal materials, a chemical reaction may occur therebetween, and thus impurities may be introduced, in which case problems of bright pixel, light leakage, image sticking and the like may occur due to the impurities when the LCD panel is used to display an image.